flashflood
Enlightened
- Joined
- Mar 9, 2011
- Messages
- 608
I've been contemplating a couple of titanium and stainless steel lights, so I decided to do a little research into their properties. The charts below show the thermal conductivity, density, and price of eleven metals and alloys of potential interest:
I couldn't find this data in any one place, so it comes from multiple sources: CRC Handbook of Chemistry and Physics, London Metal Exchange, etc.
There are many other important properties too numerous to list: strength, hardness, toughness, ease of machining, corrosion resistance, susceptibility to hydrogen embrittlement, toxicity, and so on. Rather than categorize all of these, I've simply omitted materials that are clearly unusable such as lead (soft and toxic), iron (rusts), and depleted uranium.
Several things stand out:
(1) Ti and SS are terrible heat conductors. I knew they were not as good as copper or aluminum, but had no idea that they were 10-20 times worse! Making a small, high-output flashlight out of Ti or SS seems like a death wish for the poor LED. Why do we crave this? (Full disclosure: I totally did not get Fatal Attraction. His wife was HOT! He threw that away for skanky, chain-smoking Glenn Close? :green::thinking:
)
(2) Why doesn't anyone make lights out of magnesium? It's cheap, feather-light, a decent conductor of heat, and has plenty of bling-cred (e.g. mag wheels). Is there some fatal weakness in one of its other properties?
And finally, the subject of this post:
(3) Why don't we show a little more love for humble aluminum? It ranks #2 in price (only tin is cheaper), #2 in density (only magnesium is lighter), and #4 in thermal conductivity (bested only by copper, silver, and gold). It is also durable, easy to machine, highly corrosion resistant, non-toxic, non-allergenic, and beautiful.
So for what it's worth, Aluminum, I for one think you're awesome. :thumbsup:

I couldn't find this data in any one place, so it comes from multiple sources: CRC Handbook of Chemistry and Physics, London Metal Exchange, etc.
There are many other important properties too numerous to list: strength, hardness, toughness, ease of machining, corrosion resistance, susceptibility to hydrogen embrittlement, toxicity, and so on. Rather than categorize all of these, I've simply omitted materials that are clearly unusable such as lead (soft and toxic), iron (rusts), and depleted uranium.
Several things stand out:
(1) Ti and SS are terrible heat conductors. I knew they were not as good as copper or aluminum, but had no idea that they were 10-20 times worse! Making a small, high-output flashlight out of Ti or SS seems like a death wish for the poor LED. Why do we crave this? (Full disclosure: I totally did not get Fatal Attraction. His wife was HOT! He threw that away for skanky, chain-smoking Glenn Close? :green::thinking:

(2) Why doesn't anyone make lights out of magnesium? It's cheap, feather-light, a decent conductor of heat, and has plenty of bling-cred (e.g. mag wheels). Is there some fatal weakness in one of its other properties?
And finally, the subject of this post:
(3) Why don't we show a little more love for humble aluminum? It ranks #2 in price (only tin is cheaper), #2 in density (only magnesium is lighter), and #4 in thermal conductivity (bested only by copper, silver, and gold). It is also durable, easy to machine, highly corrosion resistant, non-toxic, non-allergenic, and beautiful.
So for what it's worth, Aluminum, I for one think you're awesome. :thumbsup: